The present invention relates to the field of beverage cooling and dispensing systems.
There is a need for a compact, portable, beer cooling and dispensing system that is coupled to a keg of beer that is delivered to the site of a social event. The dispensing system should have a proper size beer cooling chamber with a high thermal efficiency to rapidly cool down the beer whereby cold beer can be dispensed from time to time to people participating in the social event. It should also be sized and configured to be easily stored and carried from place to place.
One approach for cooling and dispensing cool beer stored in a keg involves placing the keg into a refrigerator to cool the entire keg. Another approach is to place the keg in a container of ice to cool the entire keg. These approaches for cooling the entire keg at once do not fulfill the objective of providing a relatively lightweight portable device for dispensing the desired limited amounts of cool beer from a warm keg of beer from time to time during the social event.
Thompson (U.S. Pat. No. 3,865,276) discloses a portable cooling dispenser that utilizes a conductive coil of tubing that is placed in a container filled with ice and ice water which cools the beer passing through the tubing to the dispensing tap. In environments such as parties during hot summer days, the ice will often not last through the length of time of the social event and the dispensed beer will not be adequately cooled. In contrast, our dispenser can provide cool beer for extended time periods, even for several days as it employs a small economical thermoelectric cooling device.
Another approach stores the keg at room temperature and a conduit transfers the beer to the dispensing tap which is cooled by a compressor type refrigeration system as disclosed in U.S. Pat. No. 2,638,758 to Duan. Such a compressor is relatively costly and cumbersome relative to our economical lightweight thermoelectric cooling device. Additionally, the amount of beer that is being cooled at one time has an insufficient volume to allow dispensing cold beer at a normal social gathering and thus warm beer will be dispensed.
In Nakayama et al., U.S. Pat. No. 6,119,464 a Peltier cooling plate is thermally coupled to a wall portion of a water cooling chamber via a cold side heat sink. Beer from a barrel is pressurized and is passed through a coil in the water bath to a dispensing tap. A mixing propeller is also shown. This is a more complex, bulky and costly arrangement than implementation of the present invention due to the coil positioned within the water bath and the mixing propeller. The cooling chamber of our most preferred embodiment of our invention is preferably no greater than 1.50 gallons for enhanced cooling efficiency, and due to its reduced size, the need for a mixing propeller and its drive motor has been eliminated to reduce manufacturing costs. In contrast with the Nakayama disclosure, a prototype of our invention is capable of cooling approximately one gallon of beer from room temperature to less than 39 degrees F. in less than ten minutes.
Moren, U.S. Pat. No. 5,544,489 unlike the present invention, is not concerned with dispensing beer under pressure; he does however disclose a metallic probe for directly cooling non-pressurized water in direct contact with the probe. Moren states at the bottom of col. 2 that the formation and retention of ice on his probe is carried out so that newly added liquid can be efficiently cooled. This approach was initially tested and found to be inefficient, probably due to the ice blocking transfer of heat from the beer to the metal (ice is a poor heat conductor), and thus we desired to avoid formation of ice on the cool sink contacting the beer, in contrast with the teachings of Moren. This was accomplished by designing the cold sink to increase the cold sink area in direct contact with the beer. Our novel heat sink configurations, compared to Moran's solid cylindrical rod, produced better rates of heat transfer to cool the beer faster, as it is needed during a social event.